THE ALIMENTARY CANAL AND ITS APPENDAGES 167 
THE VERMIFORM PROCESS 
The processus vermiformis (ap., Fig. 99) 1s a feebly de- 
veloped organ which lies at the end of the short cecum (c@.), 
and possesses a considerable morphological interest. In Man its 
average length is 84 cm., but it may be but 2 cm.,, or on the 
other hand, some 20 to 23 cm. long. 
Considerable variation also occurs in its width and disposition 
Fic. 99.—THE CacumM AND PROcESSUS VERMIFORMIS OF A HuMAN EMBRYO. 
1.1., large intestine ; 7.s., small intestine ; cw., coecum ; ap., vermiform process. 
(cf. p. 166), and in the folds of mucous membrane which bound 
its ostium. Indeed, everything points to the retrogressive 
character of this appendage, and justifies us in concluding that 
the total length of the alimentary tract was formerly greater 
than it now is. The great variations in the form and size of 
the ececum (cw.) also support this view. 
According to Ribbert the processus vermiformis at different 
ages measures as follows :— 
